Improvement in shears for cutting metal



UNITED STATES PATENT -FFIC'E.1

GEORGE M. MARSHALL, or new HAVEN, WISCONSIN.

IMPROVEMENT IN SHEARS FOR CUTTlNG MET AL.

Specification forming part (if Letters Patent No. 122,270, dated December 26, 1871; antedated December 23, 1871.

To whom it may concern:

Be it known that I, GEORGE M. MARSHALL, of'

New Haven, in the county of Adams and State of Wisconsin, have invented a new and useful Improvement in Shears for Outtin g Metal and I do declare that the following is a true and accurate description thereof, reference being had to the accompanying drawing and to the letters of reference marked thereon and being a part of this specification, in which- Figure 1 is a side elevation of a shears constructed to embody my invention. Fig. 2 is a front elevation of the same; and Fig. 3 is an elevation of the other side.

Like letters of reference made use of in the several figures indicate like parts.

Nature of the Invention.

. This invention relates to that class of shears made use of to cut heavy metal, and chiefly employed by blacksmiths; the object being to furnish a strong durable shears at a comparatively small cost, and such, at the same time, as will enable the operator to sever heavy bar-iron at a very sharp angle. The frame or jaw-shaped support is so contrived as to not interefere with the adjustment of the bar to the desired angle; and my invention consists of a novel construction and arrangement of parts, as hereinafter more fully described.

To enable those skilled in the art to make and use my invention, I will proceed more to describe the same'with particularity,making use in so doing of the aforesaid drawing.

General Description.

A jaw-shaped standard, A, arranged to be attached or afiixed to a proper supporting-frame, holds the lower or stationary blade B of the shears. The upper or moving blade 13 is carried by a strong metal plate or frame, O,placed side by side with the jaw-shaped standard A, the contiguous sides of the plate and standard being planed or.- properly fitted to move upon one another wit-hthc.

least possible friction, and the plate secured to the standard by interchanging connections, as will be presently explained. The bearing of the plate consists ofa trunnion,T, projecting from the stan dard A into a cavity within the said plate; this trunnion is indicated upon the drawing in dotted lines. The head of the standard or upper extremity of the upper jaw thereof, above the point of the shears, is fitted witha cogged segment,D, while the correspondingpoint of the moving plate affords the pivot, fulcrum, or bearin g of a lever, E, having a geared segmental head, G, the teeth of which engage the geared segment I). A pin, L, or lug, projects from the standard at a point above the trunnion, anda second pin or lug, M,

below the moving-plate. The pin or lug L extends through a curved slot, K, cut through the moving plate at this point. A tie or retaining. bar, N, extends from one of the above-mentioned 1 pins or lugs to the other, serving to hold the plate firmly to its work; this bar being secured to the lugs by proper bolts passing thereinto. The pin -ard in the following manner: The inner end of the blade is beveled and fitted into a beveled recess within the metal of the standardor plate; the whole blade is contained in a set-off or recess within the metal; being, in brief, countersunk. The outer end of the steel blades are made plain, and a single bolt or screw,s, serves to hold them in place; the screw being applied at this point is easily gotten at, and when it is removed the whole blade may be detached readily without taking the shears apart. This proves to be a great conven ience in view of the frequent sharpening required.

Now, the operation of my invention is, briefly,

as follows: Power is applied to the leverEto bring the same down, which rotates the segmental head 0, and changes constantly the point of resistance. along the segmental gear D of the standard; or, in other words, the segmental head of the lever is rolled along said gear, carrying with it the plate attached thereto, which moves upon the trunnion T with arotatingor rockingforward motion, bringin g the upper blade of the shear therewith to produce the out. From the back of the blades the opening or jaw in the standard is cut away, in an angling direction, through the material of the standard, forming a prolongation, O, of said jaw. U l 

